Cycle 1 (2011 Deadline)
Assessment of the tropospheric HONO budget: instrumental development and field measurements
PI: Charbel Afif, Université Saint Joseph de Beyrouth
U.S. Partner: Sebastian Dusanter, University of Indiana
Project Dates: May 2012 - May 2014
Climate change is one of the most important environmental concerns of the 21st century, and there are concerns regarding atmospheric warming due to increases of greenhouse gas emissions. Reliable climate projections will depend on how well models of atmospheric chemistry can forecast concentrations of greenhouse gases, whose lifetimes depend on the global concentration of the hydroxyl (OH) radical. However, there are still large uncertainties related to the atmospheric OH budget. Recent studies focusing on the chemistry of nitrous acid (HONO), an important source of the OH radical, indicate that model-predicted concentrations of HONO do not agree with field measurements performed in various environments (urban, rural, forests, etc.). These results suggest that our understanding of HONO chemistry is incomplete and call into question our ability to model the atmospheric oxidative capacity and therefore our ability to predict future changes in the atmosphere.
The project will support construction of a reliable instrument (NitroMAC) at the Université Saint Joseph de Beyrouth to measure atmospheric HONO concentrations. The principal investigator will work to develop a calibration source of HONO and compare data collected by his new NitroMAC instrument with those gathered by his U.S. partner’s HONO instrument. NitroMAC will be deployed by the collaborating researchers during intensive field campaigns in both the United States and Lebanon, with the US partner to provide the infrastructure for field measurements and part of the equipment necessary for the intercomparison experiment. Collaborations through the field campaign measurements and subsequent data interpretation will promote the sharing of knowledge between the researchers involved. The research outcomes of the project should also benefit the atmospheric science community by adding more constraints to the HONO budget and by improving understanding of the oxidative capacity of the atmosphere. Furthermore, the project will initiate air quality studies in Lebanon and will help promote the development of efficient strategies for pollution control.
Summary of Recent Activities
Between October and December 2013, arrangements were made for the the purchase and delivery of the air quality analyzers, including consumables and spare parts to cover one year of proper functioning. Separately, the NitroMAC and NitroCal machines were shipped back from Indiana to Université Saint Joseph, arriving shortly before the end of 2013. The raw data collected using these instruments during the August 2013 Indiana field sampling campaign were being analyzed. The team has also added Dr. Adib Kfoury as a postdoctoral fellow. He will be assisting with field campaign preparations as well with as literature review.
In the first few months of 2014, the project team plans to test the instruments at USJ before deploying them in the field. The planned experiment consists of collecting an air sample from an automotive tunnel to acquire chemical data from traffic emissions, as well as a sample from campus. After these data are analyzed, findings and results will be prepared for submission.
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